Yes, I know what you mean about GPU power...how do you set up two GTX760's? Or would it be better to save up for a GTX980 Titan? Is that what they are talking about when they say Titan Blacks?
Windows 7, 8, 10 should recognize both cards. In addition, you may need to tell your renderer (Iray, Superfly, Octane), usually at the render settings that you are using both video cards.
I have both GTX760s checked, both are attached to a monitor each.. the third attached to my onboard video card. (I have a 3 x 24" LED setup) You'll notice some video slowness when you're rendering. I would only work on the screen that is attached to my onboard video for other stuff.
One of my GTX760 is 2 yr old the older about a year old, I added the second becuz it was on sale.
The 760 are older cards with older technologies. They still perform okay. They have 1152 Cuda cores with a base clock speed of 980 MHz, each of them have 4 Gb of GDDR5 memory. So two of them will have a combined 2304 cores (translation : faster renders, theoretically 2x faster), the Memory is still at 4GB (lowest denominator)
The GTX960 is a newer card (2Gb or 4 Gb). It has 1024 Cuda cores @ 1127 Mhz - As you can see, it's about the same as the GTX760 (I suspect it was a replacement card for the GTX760. --- quite affordable (less than $200)
The GTX980 Black has 2880 Cuda Cores @ 889 MHz and usually comes with 6 GB of Video Memory -- somewhat pricey ($400 +)
The GTX980 Titan X has 3072 Cuda Cores @ 1000 Mhz and comes with 12 GB of Video Memory -- expensive ($1000)
The GTX 980 Titan Z has 5760 Cuda Cores @ 705 Mhz and comes with 12 GB of Video Memory -- very expensive ($1400)
With PBR More cores will yield faster render (clock speed matters as well). More Video Memory will render more sophisticated scenes. With 2 Gb, you'll soon run out of memory if you do two Dawn's with a background . I would suggest to get at least 4G. If you have two cards, the Renderer will usually chose the card with lowest denomination of VRAM; for instance, if you have a 2 gb and a 4 gb card, it will only use 2 GB for VRAM, it won't combine them.
NOT all PBR are created equal. It depends on how the PBR are written. With the same scene, using Superfly may not give you better time than using Iray or Octane.
Note: More CUDA, faster renders, More VRAM more textures read.
Note: These cards are very power hungry. If you upgrade, invest in a good Power Supply. I'm currently using a 850W PSU , Platinum 80 rated to power those two 760s....
OKAY, I gotta unnerd myself now....I've gone crossed eye..